This F-14 simulator for FlightGear supports the F-14A, F-14B variants, with a multiplayer RIO option. The aerodynamics in the FDM are based on real wind tunnel data and cover the full range of flight operations, including stalling and realistic spinning. This F-14 simulator has a realistic F-14 Flat Spin that is unrecoverable as in the aircraft.
The F-14A with the Pratt and Whitney TF-30 engine is famously sensitive to compressor stalls, and this engine is responsible for many airframe losses. The TF-30 model includes a configurable compressor stall, including MCB failure. The compressor stall is simulated based on engine pressures (PB) and the affect of angle of attack and sideslip on the inlet airflow to produce a representative compressor stall. As the compressor stall is based on inlet pressure it is still possible to stall the engine at higher speeds during high G manoeuvering.
Detecting and handling TF-30 compressor stalls
When the compressor stalls there will be a small pop (from the corresponding side). However it is easy to miss this, and particularly on approach when coming in with surplus energy it is possible to keep this in check with rudder and stick and only when increasing power, especially into afterburer, when the yaw moment becomes uncontrollable and an airframe loss is the likely result. Monitoring the engine gauges during your scan will allow you to detect a compressor stall by the reduction in RPM. Recovery procedure is simply to move the throttle for the affected engine to idle and wait for recovery.
The Flightgear F-14B always had a beautiful 3D model and 3D cockpit thanks to Alexis Bory and Enrique Laso ; however I felt that the aerodynamics and flight model were not as good and so in August 2014 undertook to fix this using JSBSim and real wind tunnel F-14 aerodynamic data. This is my first flightgear model; although I've been working with flight simulators for many years professionally.
Once I'd fixed the flight model there were a few changes that just had to be made; I felt that the lack of hydraulics and electrics detracted from the realism and provided a challenge to implement these using JSBSim rather than in Nasal. Using JSBSim for none FDM modelling works well.
The JSBSim aerodynamics model uses all of the data in the AFWAL-TR-80-3141 report and is accurate for low speed clean configurations. I have modelled the high speed and flaps etc. based on other reports so these may not match the aircraft precisely.
Because of the more realistic model the aeroplane is harder to fly than those with simpler aerodynamic models (e.g. High-G turns you need to watch the AOA to ensure that you don't stall the wings or the ailerons/stabilators)
I've also redone most of the sound effects to make it what I consider more realistic and improved the cockpit to add missing gauges.
Realistic JSBSim aerodynamic model with high speed and full wing sweep modelling based on real F-14A data. There are 63 distinct detailed aerodynamic coefficients)
- High alpha handling – including dutch roll and control reversal as described in the pilot's manual
- Accurate stalls, spins, and other departures (including flat spin)
- Wing sweep (20-68) has aerodynamic effect
- Gear effects on aero (pitch, lift, drag)
- Flaps (pitch, lift, drag)
- Wing sweep (including manual sweep). Sweep interlocks are correctly modelled so when deploying flaps aux flaps can only be used below 22deg of sweep; otherwise up to 50degrees the main flaps can be deployed. At wing sweep of more than 55 degrees no flaps are available.
- CADC Maneuvering flaps / slats (again modelled on best available aero data)
- Differential spoilers accurately modelled - so at high alpha or high wing sweep roll rate is reduced (spoilers only effective up to around 10degress AOA; and less than 55deg wing sweep)
- Electrics system model (Mainly for JSBsim)
- Hydraulics systems (Mainly for JSBsim)
- F110 engine performance remodelled (data from NASA-TM-104326) which is more accurate than the previously used values
- Contrails from the wings at high alpha subject to atmospheric conditions.
- AFCS tuning; the altitude hold is implemented in the CADC model; the normal autopilot is used for heading and throttles.
- Added smoke generator (ground services dialog)
- Added the option for an extended HUD. This isn't realistic it's just useful. So the purists who want an F-14B HUD this can be turned off in the ground services dialog
Acurately modelled based on:
- AFWAL-TR-80-3141 Investigation of High-Angle-of-Attack Maneuver-limiting factors
- Pilot's manual (NATOPS) F14-AAD-1
- NASA TN D-6909 DYNAMIC STABILITY DERIVATIVES AT ANGLES OF ATTACK FROM -5deg TO 90deg FOR A VARIABLE-SWEEP FIGHTER CONFIGURATION WITH TWIN VERTICAL TAILS
- Engine noises made from 5 components (intake, N1 whine, N2 whine, efflux, Augmentation); intake and efflux as based on EPR rather than thrust as this gives more realistic results
- Landing gear touchdown and skidding
- Bump / rattle noises based on what's happening with the gear strut compression.
- Flap & Gear extended wind noise
- High alpha vortex noise
- Flap & Gear extension reworked to something that is more hydraulic sounding. Not sure if this is right but it sounds less like a Cessna
- Canopy open / close
- Wind noise
- Gear wind noise
- Flaps and airbrake wind noise
- Ground bumps and ratlles
- Scrape / fuselage contact
- Auto wing sweep now in FDM for improved fidelity. Wing sweep follows F14-AAD-1 so generally fully swept by M 0.9
- SAS (roll, pitch, yaw in FDM)
- Engine quickstart from menu
- Predefined fuel loads added to external loads panel together with showing the CG%.
- Can do in cockpit engine start
- Added NASA 834 livery.
- Wingtip contrails at high alpha
- Engine contrails reworked slightly
- Master warn panel with working indications for engs, fuel, hydraulics, electrics.
- Engine control panel (crank, ramps, rudder trim switch )
- Elevator / Rudder and spoiler gauges now connected to surfaces.
- Oil pressure gauges
- Connected elevator & rudder position gauges to surfaces
- Fuel cut off on glareshield works (need this for engine start)
- In cockpit engine start & shutdown possible.
- Anti-Skid / spoiler brake switch connected
- EGT display correct for F110
- Hydraulic pressure gauge
- Hyds transfer panel
- Master generator control panel (you can turn off the generators and emergency generator and will have no electrics)
- ARA 63 panel
- Master test panel
- Moved fuel tanks so that the CG% is roughly correct and generally within the range of the pilot's manual.
- Added shortcut buttons for pre-defined fuel loads.
The hydraulics and electrics require either engine systems or external power. So if you lose engines at low speed (insufficient airflow to keep the turbines spinning) then you will also lose electrics and hydraulics and thus flight controls
An engine start can be performed by pulling the cut off values (yellow stripy each side of the glare panel) and selecting crank (with or without external air). Once the engine N2 reaches above 18% the hyrdaulics will have sufficient pressure to power the backup electrical generator and the cockpit should light up.
As all of the simulation models are in JSBSim (rather than Nasal) it runs much faster and gives a much more fluid and realistic response.
The brakes control binding for joysticks will function as either ground or airbrakes appropriately.
- Revisions to the ground handling, aerodynamics, hook and catapult to fix the reported problems with landing on, and taking off from carriers
- ARA-63 carrier landing system, you can turn if off from the panel on the right hand side next to the master caution if you don't want it
- Less odd afterburner sounds.
- Revisions to the lift/drag coefficients for flaps between 10 and 35
- Corrections to ground contact points
- Afterburner added to replay
- Better carrier operations and lighting based on scene available light for particle trails (credit to Thorsten Renk)
- Implementation of limits (credit to onox)
- Fixed indicated AoA based on ADA101648 p84
- Wired up the speedbrake to j/k keyboard bindings and joystick Spoilers Retract/Deploy
- Louder cockpit noises when cockpit open (credit to onox)
- Aerodynamic tuning for flaps / slats, gear positions
- The hook now has the correct geometry so it will drag along the ground and catch properly.
- Fixed the tail appearing to disappear below ground on touchdown
- Corrected geometry for landing gear.
- Added carrier launch/approach reposition and set tower to ground services dialog (based on the TACAN tuned carrier)
- Revised the spring/damping coefficients to prevent ridiculous bounciness after or during a crash.
- Pitch instability fixed
- Uses ALS secondary lighting for taxi lights
- New F-14A (with TF-30 and compressor stall)
- Flight modelling of aerodynamic effects when wing torn off.
- Backlit panels
- New canopy glass, including frosting and glare effects.
- ALS interior effects.
- ECS systems
- New Afterburner models (3d and FDM)
- New altimeter (as per aircraft)
- Revised gauges to match aircraft: Acceleration, ASI, VSI, Radalt,
- New Liquid oxygen gauge, cabin pressure, and ECS panels.
- Removed coarse cockpit for better FGCamera support
This work is licensed under the GPL v3